Fuel Audit Log Printing

As part of the enhancements for the fuel module, to make it work faster, we decided to put the fuel audit printing and auto-stacking into a separate thread. This sounds relatively simple, but there were a few issues to deal with. The main one was that talking to the enabler (the fuel system interface we use) does not work when called from another thread.

To get around this, we decided to make the new thread print deliveries that have been added into the database. The problem with this is that the database record does not get entered until someone does something with the delivery. So the process is as follows:

• On the master fuel till, a delivery is placed into the database as soon as it is created. This is done in the main thread via an event from enabler.
• In the new thread, we look in the database for any deliveries in the database that have not yet been printed and print them. This is flagged in the database.
• We then perform the auto-stacking in the same place as before, in the main thread. The main difference is that now the main thread is not held up by the printing, making the system more responsive.